Process of dyeing



UNITED PATENT orriciei HANS 'I'OEPFER, 0F INEKV YORK, N. 32"., ASSIGNQB I'D THE GRASSELLI GI-IEIVZICAL COMPANY, OF CLEVELAND. OHIO A CORPORATION 033 OHIO.

} PROCESS OF DYEING.

No Drawing.

T 0 (LN 10 7mm it may concern:

Be it known that I, HANs Tonrrnn, a citizen of Germany, residin at New York city, in the county of New York and State of New York, have invented certain new and useful Improvements in Processes of Dyeing, of which the following is a specification.

It is a general practice to treat the animal fibres dyed with the so called mordant colors with chromium salts in order to obtain the desired shades and fastness properties. In such dyeing processes the chromium salts can be applied to the animal fibres before dyeing, they can be added to the dye bath, or the dyed goods can be after treated with chromium salts. With the exception of copper salts which are used in a few instances, no other salts of heavy metals have ever found a practical application for the treatment of dyed animal fibres.

I have now found that the shade and fastness of animal fibres, that is to say wool. and

silk, dyed. with azo colors having as one component ortho-amidophenol with one or more nitro-groups in the same benzene nucleus can be greatly improved by using in conjunction therewith a cobalt salt. This may be done either by applying the dyestufi after the fiber has been mordanted with cobalt salts; or by adding cobalt salts to the dye bath: or preferably by utter trez'iting the dyed fibre with cobalt salts.

As examples of such nitro-ort-hoamidophenol azo dyestuffs I may mention:

(1.) The combination of picramic acid and naphthionic acid described in Schultz-Julius #91:

(2) The compound Nb2 oi described in U. S. Patent 936,321, Oct. 12,

Specification of Letters Patent.

Application filed August 4, 1921.

Patented May 30, 1922.

Serial No. 489,849.

843,077, Feb. 5,

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described in U. S. Patent 1,159,375, Nov. 9, 1915, but I wish it understood that our invention is not limited to the above mentioned dyestuffs.

In order to illustrate more fully the new process, the following examples are given:

Emample J.-100 parts of wool are dyed in the usual way with 2 parts of the dye stuff prepared by coupling naphtionic acid with diazotized picramic acid (Schultz- Julius #91) 10 parts of Glaubers salt and 2 parts of acetic acid are added and the bath is heated to boiling for of an hour. part of sulfuric acid is then added in order to exhaust the dye bath and boiled for 15 minutes longer; thereafter 2 parts of cobalt sulfate, or an equivalent amount of cobalt chlorid or cobalt acetate are added and boiled for it; hour. The dyed goods are rinsed. A green shade, very fast to light is obtained. It is much brighter than the one obtained by after treating the same dyeings with other metal salts, e. g, chrome. This shade has further the advantage of being as brilliant under artificial light as by daylight.

Example 2.100 parts of wool are mordanted with 3 parts of cobalt chlorid and 1 part of" acetic acid boiled for 1 hour and rinsed. The goods are entered cold into a dye bath containing 2 parts of the dyestufi prepared according to U. '53. Patent 843,077 of Feb. 5, 1907, and 2 parts of: acetic acid, heated to the boiling temperature, boiled for 1 hour and rinsed. A light fast blue shade is obtained.

Example 3.-A dye bath is prepared from parts of water, 2 parts of cobalt chloride and 2 parts of the dyestuff prepared according to U. S. Patent 986,321 of Oct. 12, 1909. parts of wool are entered at F. The dye bath is brought up to the boiling temperature, boiled for g hour, then 2 parts of acetic acid are added and boiled for 3; hour longer. The dyed goods are rinsed, A dark brown shade is obtained which compares very favorably in light fastness to the brown obtained in a bichromate bath.

I claim 1. In the art of dyeing animal fibres, the process comprising using cobalt salts in conjunction with azo dyestuffs derived from. nitro-ortho-amidophenols.

2. Process according to claim 1 in which the cobalt salts are applied to the dyed fibre.

In testimony whereof, I ailix my signature.

HANS TOEPFER. 

